Alginate utility in edible and non edible film development and the influence of its macromolecular structure in the antioxidant activity of a pharmaceutical/food interface

MARÍA DOLORES DENOBILI; LUCRECIA MARÍA CURTO; JOSÉ MARÍA DELFINO; CAROLINA DAIANA PÉREZ; DANA BERNHARDT; LÍA NOEMÍ GERSCHENSON; ELIANA NOEMÍ FISSORE; ANA MARÍA ROJAS

Alginic Acid: Chemical Structure, Uses and Health Benefits

Nova Science Publishers, Inc.

Año: 2014; p. 119 - 169

Edible films and coatings are mostly investigated as an interesting alternative for food packaging. Edible films habitually developed for food protection are very good barriers to gases but not to water vapor because polysaccharides and proteins have to be used for their development. Nowadays, there are many research works which look for decreasing film permeability to water vapor. Beyond this fact, edible films are much studied matrices since they can be also applied as a technological hurdle for food preservation because their microstructure can be used to carry, stabilize, localize the activity and control the release of food preservatives (antimicrobials, antioxidants) at interfaces. For non edible purposes, films can be also applied for wound dressings as drug delivery systems to improve wound healing. Also, to tissue engineering. Alginate polymers have long been used in the food and beverage industries as thickenners, gel-forming and colloidal stabilizing agents. Alginates are also used in the pharmaceutical industry as matrices for drug encapsulation, as substrates for cell culture, as binders for medical tablets and for many applications of controlled drug delivery. Alginic acid is a natural unbranched binary copolymer constituted by (1,4)-linked -D-mannuronic acid (MM-block) and -L-(1,4)-linked guluronic acid (GG-block), as well as by sequences of alternating -D-mannuronic and -L-guluronic acid (MG- and GM-blocks), producing different macromolecular structures of alginates. Physical and mechanical properties as well as biocompatibility of alginate materials are highly dependent on the relative content of L-guluronic to D-mannuronic acids. Calcium ions can replace in part the hydrogen bonding, zipping guluronate (but not mannuronate) chains together in an ?egg-box? conformation. A decrease in the swelling rate constant with elevated calcium concentration was determined. As a consequence, the release of embodied active compounds in alginate matrices will be also delayed, allowing these systems to be used in controlled release of drugs and food preservatives. This fact makes of alginic acid an interesting biopolymer for being applied to film development. This chapter reviews in recent literature, the utilization of alginates to the development of films applied to food and pharmaceutical formulation. Since it is generally observed that researchers rarely know and consider the composition of the alginate that they used for film development, a study where the influence of the alginate copolymer composition on the stability of the L-(+)-ascorbic acid supported in films is also reported. They were obtained for acting as controlled delivery systems for nutritional supplementation, therapy or antioxidant activity at interfaces.